Annual report / Forschungszentrum Jülich Institut für Kernphysik. 1990
Annual report / Forschungszentrum Jülich Institut für Kernphysik. 1990
The work carried out by the members of the Institut für Kernphysik (IKP) of the Forschungszentrum Jülich, (KFA), was concentrated on building in close cooperation with other groups in the KF A the cooler synchrotron COSY -Jülich, improving the cyclotron as injector and planning and perparing experim...
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Personal Name(s): | Kilian, Kurt (Editor) |
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Krewald, S. (Editor) / Maier, Rudolf (Editor) / Rossen, P. von (Editor) / Schult, Otto W. B. (Editor) / Seyfarth, Hellmut (Editor) / Speth, J. (Editor) / Turek, P. (Editor) | |
Contributing Institute: |
Publikationen vor 2000; PRE-2000; Retrocat |
Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
1991
|
Physical Description: |
293 p. |
Document Type: |
Report Book |
Research Program: |
ohne Topic |
Series Title: |
Berichte des Forschungszentrums Jülich
2462 |
Link: |
OpenAccess |
Publikationsportal JuSER |
The work carried out by the members of the Institut für Kernphysik (IKP) of the Forschungszentrum Jülich, (KFA), was concentrated on building in close cooperation with other groups in the KF A the cooler synchrotron COSY -Jülich, improving the cyclotron as injector and planning and perparing experiments to be carried out at COSY. This was accompanied by theoretical studies related to medium energy nuclear physics experiments and other research and development work in close connection with COSY physics. Twelve of the total of 24 COSY dipole magnets have been set up in their final positions, 16 have been measured. The quadrupole and sextupole magnets, those for the extraction lines, and others are under fabrication. Work proceeds as planned on the electron cooler, on the diagnostic and stochastic cooling components, and in the field of COSY control including the injector. Software is being developed using HP-UX systems. On May 1 the ISI-COSY group was integrated into the IKP-COSY accelerator group. Commissioning of the new RF power supply for the injector cyclotron has been started and first tests of the acceleration structure were carried out. An H$_{2}$+ source has been developed. Highly charged light ions, like 162 keV $^{20}$Ne$^{9+}$, are available at the ECR source for atomic physics research. In order to provide space for experiments with beams extracted slowly from COSY, the old beam-line system was disassembled. The components have been made available for interested groups in other research institutes. During the last year also the other preparations have been completed so that installation of the COSY injection beam line can be started. Further planning of COSY experiments resulted in five additional proposals. A largeamount of work was carried out in order to realize major multipurpose facilities: the upgraded magnetic spectrometer BIG KARL for ejectiles with momanta up to 1.1GeV/c and the 10 m long, 1.5 m radius time of flight spectrometer TOF, both for external experiments, and a magnet facility for internal experiments even under 0$^{0}$ and for ejectile momenta up to 3.3 GeV/c. Research and development work was continued for preparation of the COSY experiments. It inlcudes developments for a high-energy photon spectrometer suitable for operation at high rates, a two dimensional position sensitive germanium wall detector, a vertex detector, Monte Carlo simulations, construction of the vacuum tank for the TOF detector, a cluster jet target and a vacuum chamber including the source holder for ribbon targets for internal experiments. Essentially all of this work is being performed in very close collaboration with scientists from neighbouring universities and other institutions in Germany and in other countries. In particular, the concept for COSY data acquisition has been worked out by a CANU team, aiming at the optimum coherence of the participating groups. Scientists from the IKP have also participated in research done in other laboratories. Work going on in the field of theoretical nuclear physics is strongly connected with research plans at COSY and processes induced in the proton-antiproton interaction. Within a nonlinear meson field theory numerical simulations of soliton-soliton collisions have been performed to extract the nucleon-nucleon potential. For the first time, within such models, medium range attraction was found in the spin scalar-isospin scalar channel. At LEAR/CERN the angular distribution of $\overline{p}p \rightarrow \overline{\Lambda}\sum^{0} + \Lambda \sum^{0}$ was obtained with unprecendented accuracy (PS185). Comparison with $\overline{\Lambda}\Lambda$ could show the influence of isospin onthe quark level. The PS202 $\overline{p}$p $\rightarrow$ 4K, search for gluonic matter was started with the first successful use of the three-Iayer scintillator hodoscope that will also be part of the COSY TOF detector. An experiment is planned for high resolution spectroscopy of $\overline{p}$p X rays. Through spectroscopy with OSIRIS three superdeformed bands were observed in nuclei near $^{146}$Gd. One band is very similar to that in $^{146}$Gd, which demonstrates its special symmetry. The 3-particle structure of high-spin states in $^{149}$Tb was identified. Its 3-particle phonon excitations agree with expectation. The evaluation of data taken previously with our fission fragment separator JOSEF has yielded information on deformations of $^{103}$Nb, $^{105}$Mo, subshell closure effects, and single-particle and two-phonon states in $^{96}$Zr. One of the last experiments carried out with our cyclotron, before itslarger shut down, has yielded unexpectedly large cross sections for $\pi^{0}$ production in the bombardment of nuclei with $\alpha$-beams. The KFA in general and the IKP in particular is advised by the Scientific Council COSY and the IKP Beirat, two committees, which have been united in 1990, by the Program Advisory Committee and the Machine Advisory Committee, and the Committee "Experiment-Beschleuniger". As managing director of the IKP, I would like to express my sincere thanks to all members of these committees for their advice and to the board of management of the KFA for the support that is given our institute. |